Poor wastewater management coupled with lack of sanitation facilities has aggravated the sanitation challenges in developing countries. This study was aimed at providing information on the current state of sanitation in Cotonou City through surveys. The most common sanitation facilities in the city were septic tanks, latrines and soakaway pits. Mechanical desulging was mainly used (94%) for desludging latrines and septic tanks with a frequency of less than once a year for 73% of the houses; manual desludging was most common for soakaway pits. 84% of sullage generated is disposed without treatment. The only existing stabilization pond plant, managed by a private company SIBEAU, is overloaded; the effluent is poor (up to 2250mg/l BOD5) and does not meet any quality standards. 96% of survey respondents recognise that the sanitation situation in the city is not good; it has to be improved by providing an appropriate and sustainable sanitation management system.

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The present study aims to fill the data gap analysis in urban wastewaters characteristics in Benin and its statistical analysis. Physicochemical parameters such as pH, electrical conductivity (EC), Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5), Total Kjeldahl Nitrogen (TKN), Total Phosphorus (TP) and UV Absorbance at 254 nm, were determined on domestic (greywater and blackwater) and industrial (hospital, pharmaceutical and commercial laundry) wastewater in Cotonou city. Analysis of variance showed a strong significant difference in the physico-chemistry of the various effluents. The pharmaceutical wastewater has the highest concentration of organic pollution (COD = 5,912 ± 1,026 mg/L, Abs.UV254 = 2.667 ± 0.327 cm−1). The organic load of blackwater is mainly in particulate and biodegradable form. Besides, the correlation study showed the limits of pH and EC as an indicator of organic load. Furthermore, the choice of COD or BOD5 as the main design parameter would be limited to blackwater treatment. Abs.UV254 was found to be the parameter having a strong relationship with other parameters of all effluents except blackwater. It then takes priority over COD for the treatment of greywater and industrial wastewater. For future wastewater treatment plant design, we recommend to consider Abs.UV254 as an important parameter.

Since many years ago, the substitution of cement by other cementitious supplementary elements has being a purpose for many researchers. This is to reduce the impact of producing cement on our environment. In this article, we are interested in the possibility of substituting cement with titanium dioxide and titanium dioxide + fly ash. To achieve this purpose, we have manufactured mortars and cement pastes specimens with different rates of replacement of cement by titanium dioxide (0%, 0.1%, 1%) on the one hand and titanium dioxide + fly ash on the overhand. The flexural and compressive strength of each specimen has been determined.

This study is part of a project to develop a bio-based material meeting the criteria of sustainable development in the field of construction. A study was then made on a cement matrix composite reinforced by aggregates of Borassus aethopium mart (palmyra). For this purpose, studies of cement compatibility with this plant aggregate, the physical, mechanical and thermal behavior of the concrete were performed for two granular compositions. The compatibility study revealed that palmyra aggregrates, although not previously treated, are compatible with Portland-limestone cement. The characterization tests focused on the mechanical properties of three-point flexural tensile strength and compressive strength and thermal properties such as effusivity, conductivity and diffusivity. The results obtained are promising: they have very good mechanical and thermal characteristics, considering its use in construction. The mechanical strengths reach 16.25 MPa for a density less than 1500 kg / m3. The thermal conductivity varies between 0.270 and 0.415. They can be used for the manufacture of panels used in the realization of suspended ceilings and tiles for the realization of roofs.